Multi-position control valve



Dec. 8, 1959 c. A. L. RUHL ETAL 2,916,049

' MULTI-POSITION CONTROL VALVE Filed Sept. 15, 1958 2 Sheets-Sheet 1 m 1NH AH w an A s 1 e r I 3 5% a h a C n w v Pfi om w n! 8 mm m 0% m3 m4mm;

5% ma EW 5 i ATTORNEYS United States Patent F 2,916,049 MUL'IKI-POSITIONCONTROL vALvE Charles A. L. Rob] and Charles J. Worth, Kalamazoo, Mich.,assignors to The New York Air Brake Company, a corporation of New JerseyApplication September 15, 1958, Serial No. 7 61,145

6 Claims. (Cl. 137-622) F 1 This invention relates to control valves,and more particularly to control valves of the solid plunger type. Asused herein, the term solid plunger valve means a valve in which one ofthe relatively movable valving elements contains no internal passages.

A typical device of this type is an open-center valve which, togetherwith a reservoir, a pump and a doubleacting differential area pistonmotor, forms a control system for positioning the earth-moving blade ofa bulldozer. Usually these valves have four operative positions, viz: araise position in which the pump and reservoir are connected withopposite sides of the motor; a lower position in which the pump andreservoir connections with the motor are reversed; a neutral or holdposi-.

tion in which the connection with each side of the motor is blocked andthe pump is unloaded to the reservoir; and a float position in whichboth sides of the motor are placed in communication with the pump and anunloading path is established between the pump and the reservoir. In thepast, solid plunger valves affording these four operative positionsprovided only a single flow path between the pump and the motor in theraise and lower positions. Because of this, the pressure losses in thesevalves were relatively high.

The object of this invention is to provide a solid plunger control valvecapable of affording the four operative positions mentioned above whichestablishes two parallel flow paths between the pump and the motor inboth the raise and lower positions and yet is simple and inexpensive tomanufacture.

. In addition, the valve of this invention affords a fifth or powerfloat position in which both sides of the motor are connected with thepump and the two sides of the motor and the pump are connected inrestricted communication with the reservoir. The provision of this fifthposition permits dropping of the bulldozer blade without causing thepiston motor to cavitate. The advantages of having both a float and apower flo a position are described in detail in copending applicationSerial No.

702,147 of Henry A. Vander Kaay, filed December 11,

1957, and assigned to the same assignee as the present application.

The preferred embodiment of the invention will be described in detailwith reference to the accompanying drawings, in which:

Fig. l is an axial section of an open-center longitudinallyreciprocating plunger valve incorporating the invention; theplungerbeing shown in its neutral position.

Fig. 2 is a sectional view taken on line 2-2 of Fig. 1 showing thecross-over passageway 31.

Fig. 3 is a view similar to Fig. l but showing the plunger in its raise"position.

Fig. 4 is a view similar to Fig. l but showing the plunger in its lowerposition.

Fig. 5 is a view similar to Fig. 1 but showing the plunger in its floatposition.

Patented Dec. 8, 1959 Fig. 6 is a view similar to Fig. l but showingthe.

plunger in its power float position.

Referring to Figs. 1 and 2, the valve comprises a housing 11 havinginlet and exhaust passages 12 and 13, respectively, and two motorpassages 14 and 15. Extending through the housing is a valve bore 16encircled by nine longitudinally spaced annular ports 17 through 19 and21 through 26. The valve bore 16 is counterbored at 27 to provide alongitudinal extension of annular port 17. Ports 21 and 23 communicatewith inlet passage 12 via passage 28, while ports 17, 22 and 26communicate with exhaust passage 13 via passage 29. A cored passageway31 interconnects annular ports 19 and 24. Conventional relief valve 32by-passes pressure fluid from passage 28 to passage 29.

Mounted in bore 16 is a slida-ble solid plunger 33 formed with fourlongitudinally spaced grooves 34, 35, 36 and 37 which define valve lands38, 39, 41, 42 and 43. Associated with the left end of the valve plunger33 is a spring-biased detent 44 which is arranged to seat in the annulargrooves 45, 46, 47 and 48 formed in the cap 49 to define four operativevalve positions. A fifth operative valve position is afforded when theplunger is moved to the left so that detent 44 overtravels groove 45 andthe end of the plunger 33 contacts the wall 51 of the cap 49.

Operation In operation, inlet and exhaust passages 12 and 13 areconnected with a pump and reservoir (not shown), respectively, and motorpassages 14 and 15 are connected with the opposite sides of a pistonmotor 52 by lines 53 and 54, respectively. With the plunger 33 in itsneutral position (Figs. 1 and 2), fluid entering inlet passage 12 passesfreely to the reservoir via passage 28, annular ports 21 and 23, plungergrooves 35 and 36, annular port 22, passage 29, and exhaust passage 13.The motor passages 14 and 15 are isolated from each other and from inletand exhaust passages 12 and 13 by plunger lands 38, 39, 42 and 43.

In order to raise the piston of motor 52, the operator moves the valveplunger 33 to the right to the raise position shown in Fig. 3. In thisposition, plunger lands 39 and 41 interrupt communication between inletand exhaust passages 12 and 13 and the fluid delivered by the pump flowsto the rod end of motor 52 via passage 28, annular port 21, plungergroove 34, annular port 18, motor passage 14, and line 53. Pressurefluid is also delivered to the rod end of the motor 52 along a pathincluding annular port 23, plunger groove 36, annular port 24,passageway 31, and annular port 19. Fluid is exhausted from the pistonend of the motor 52 to the reservoir via line 54, motor passage 15,annular port 25, plunger groove 37, annular port 26, passage 29, andexhaust passage 13. When the piston of motor 52 has moved the desireddistance, the operator returns the plunger 33 to its neutral position,cutting off flow to and from the motor 52 and unloading the pump.

In order to lower the piston of motor 52, the operator moves the plunger33 to the left from the Fig. 1 position to the lower position shown inFig. 4. In this position,

plunger lands 41 and 42 interrupt communication between inlet andexhaust passages 12 and 13. High pressure fluid flows to the piston endof motor 52 via passage 28, annular port 23, plunger groove 37, annularport 25, motor passage 15, and line 54. A parallel supply path isprovided by annular port 21, plunger groove 35, annular port 19,passageway 31, and annular port 24. The rod end of the motor isexhausted to the reservoir via line 53, motor passage 14, annular port18, plunger groove 34, annular port 17, passage 29, and exhaust passage13.

When the valve plunger 43 is shifted further to the left and detent 44engages groove 45, the valve will be in the float position shown in Fig.5. In this position, the two motor passages 14 and 15 are interconnectedby annular port 18, plunger groove 35, annular port 19, passageway 31,annular port 24, plunger groove 37, and annular port 25. Thisinterconnecting path communicates with inlet passage 12 via plungergroove 37, annular port 23, and passage 28. It should be noted that theunloading path between inlet passage 12 and exhaust passage 13,comprising passage 28, annular port 21, plunger groove 36, annular port22, and passage 29, is unrestricted. Therefore, in this position, motor52 can reciprocate freely under the influence of external forces withoutloading the pump.

Shifting of the plunger 33 to the left from the Fig. position causes itto take up the power float position shown in Fig. 6. Theinterconnections between the passages 12, 13, 14 and 15 in this positionare the same as those established in the float position of Fig. 5 exceptthat in this case, the left edge of valve land 42 restrictscommunication between annular ports 21 and 22 through plunger groove 36.The amount of this restriction depends on the characteristics of theparticular installation in which the valve is used. In some cases, itmay be necessary to interrupt this communication in order to provide thevolume and pressure required to maintain the expanding chamber of motor52 filled with fluid. Because of this, it will be understood that theterm restricted is used herein to mean partially obstructed as well asclosed.

It should be observed that passageway 31 functions as an active fluidconduit in all operative positions except the neutral position shown inFig. 1. This factcontributes to the simplicity of the valve housing.Furthermore, it should be noted that in both the raise and lowerpositions of the plunger 33, the passageway 31 provides a parallel flowpath between the inlet passage 12 and the motor 52. This feature reducesthe pressure losses in the valve because, as is well known, the totalrestriction to flow between two points through a plurality of parallelpaths is less than the restriction afforded by any one of the pathsacting alone.

As stated previously, the drawings and description relate only to apreferred embodiment of the invention. Since many changes can be made inthe structure of this embodiment without departing from the inventiveconcept, the following claims should provide the sole measure of thescope of the invention.

What is claimed is:

l. A valve comprising a housing containing a first valving surfacehaving nine spaced ports, namely, a central exhaust port, right and leftouter exhaust ports located on opposite sides of the central exhaustport, right and left motor ports located between the central exhaustport and the two outer exhaust ports, right and left cross-over portslocated between the central exhaust port and the two motor ports, andright and left inlet ports located between the central exhaust port andthe two cross-over ports; a flow passage connecting the two cross-overports; a second valving surface cooperating with the first valvingsurface and having five valve lands separated by four valve grooves,there being a central land, left and right outer lands located onopposite sides of the central land and left and right middle landslocated between the central land and the two outer lands;

and means for moving one valving surface relatively to the other, theports, grooves and lands being so dimensioned that the valve has: afirst operative position in which the two middle lands and the two outerlands isolate the two motor ports; a second position in which thecentral land and the left middle land isolate the central exhaust port,the groove between the right middle and right outer lands connects theright motor port with the right outer exhaust port, the groove betweenthe left middle and left outer lands connects the left motor port withboth the left cross-over and left inlet ports, and the groove betweenthe central land and the right middle land connects the right inlet portwith the right cross-over port; and a third operative position in whichthe central land and the right middle land isolate the central exhaustport, the groove between the left middle and left outer lands connectsthe left motor port with the left outer exhaust port, the groove betweenthe right middle and right outer lands connects the right motor portwith both the right cross-over and right inlet ports, and the groovebetween the central land and the left middle land connects the leftcross-over and left inlet ports.

2. The valve defined in claim 1 in which there is a fourth operativeposition in which the groove between the central land and the rightmiddle land connects. the left inlet port with the central exhaust port,the groove between the central land and the left middle land connectsthe left motor port with the left cross-over port, and the groovebetween the right middle and right outer lands interconnects the rightinlet, right cross-over and right motor ports.

3. The valve defined in claim 2 in which there is a fifth operativeposition having the same port interconnections as in the fourth positionbut in which the right middle land restricts the communication betweenthe left inlet port and the central exhaust port through the groovebetween the central land and the right middle land.

4. The valve defined in claim 1 in which in the first operative positionthe two grooves separating the central land and the two middle landsconnect the two inlet ports with the central exhaust port.

5. The valve defined in claim 4 in which there is a fourth operativeposition in which the groove between the central land and the rightmiddle land connects the left inlet port with the central exhaust port,the groove between the central land and the left middle land connectsthe left motor port with the left cross-over port, and the groovebetween the right middle and right outer lands interconnects the rightinlet, right cross-over and right motor ports.

6. The valve defined in claim 5 in which there is a fifth operativeposition having the same port interconnections as in the fourth positionbut in which the right middle land restricts the communication betweenthe left inlet port and the central exhaust port through the groovebetween the central land and the right middle land.

References Cited in the file of this patent UNITED STATES PATENTS1,099,161 Brown June 9, 1914 2,109,162 Boehle Feb. 22, 1938 2,610,022Meddock Sept. 9, 1952

